> Are the scientists interacting?
So say Alice and Bob interact, forming an event in RQM. Then they both separately interact with Charlie, generating two new events. These two new events are, in general, related (correlated) to each other, because they may be causally influenced by the original event. (For example, Alice tells Bob the number. They both send this number to Charlie.)
> Not hearing something, in any way, simply means you have not yet interacted with it. There has been no exchange of information. It doesn't mean it didn't exist.
My intuition agrees with yours here, but I think RQM is saying something different. The article says that in RQM, variables simply don't have any value unless a system acts on another system. Here is the relevant quote.
> Variables have values when a system acts on another system. More precisely, for a system S to have a variable A taking a value is to interact with a second system S′; the variable A characterizes the effect of a certain action on S′
And about the tree falling in the forest, I take it to be more of a metaphysical question about existence. In the real world, a tree falling is an extremely complex system and will inevitably interact with many other systems -- the air, the ground, like you said. But the heart of the issue is whether it's meaningful to talk about a tree which is somehow isolated from the rest of the universe.